The cumulative price multiplier over the four years is $(1.02)(1.03)(1.05)(1.08) \approx 1.191$.

The average annual inflation rate is calculated as the geometric mean of the annual inflation factors minus $1$: $\sqrt[4]{1.02 \times 1.03 \times 1.05 \times 1.08} - 1 \approx 4.47\%$.

The arithmetic mean of the inflation rates is $4.5\%$.

The geometric mean of the inflation rates is always less than or equal to the arithmetic mean of the inflation rates.